1. Field of the Invention
The invention relates to a method for roof drainage for reducing urban waterlogging.
2. Description of the Related Art
Roofs of modern buildings are equipped with drainage devices. Drainage exits of the drainage devices are arranged on low-laying areas on the roof for draining the accumulated water, particularly the accumulated water formed within a short period during a cloudburst, out of the building. Typical methods for roof drainage target at accumulating and draining the water out of the building as soon as possible, which facilitates the accumulation of rainwater on the ground of the city. However, with the enlargement of areas impervious to water, such as concrete constructions, asphalt pavements, and parking lots, water flow and the peak flow thereof on the ground surface of the city increase, thereby resulting in more and more urban waterlogging. Disadvantages of conventional methods for roof drainage lie in that the rainwater on various underlying surface is drained simultaneously and the peak flow of the surface runoff is too high, which easily results in urban waterlogging in case of frequent and heavy rainfalls.